It is generally known in the art to use a top loading gravity flow apparatus for charging bulk materials to a pneumatic transport pressure vessel. Typically, these conventional top loading gravity flow devices require high headroom and a large amount of horizontal plant floor area. In many existing facilities, the required amount of headroom and plant floor space is limited and the conventional gravity flow top loading apparatus is not economical. In the conventional system, material chips, such as wet or dry metal chips (with or without coolant fluid), are conveyed to a vibrating storage hopper mounted above the transport pressure vessel which stores material for subsequent gravity feeding to the pneumatic transport pressure vessel. An inclined screw conveyor elevates the chip materials above the pneumatic transport pressure vessel for top loading by gravity feed from the discharge of the vibrating storage hopper. The top of the pneumatic transport pressure vessel is sealed by means of a dual valve configuration allowing pressurization of the pneumatic transport pressure vessel for conveying.
It is generally known in the art to use switch valves for switching the connection from the discharge of the pneumatic transport pressure vessel between two alternate discharge pipes leading to different discharge collection points. Many of these switch valves use an inflatable pneumatic seal which is unacceptable for use in conveying metal chips, since the metal chips readily puncture the inflatable pneumatic seal. In addition, many of these switch valves are limited in use to applications where the switch valve is clear or empty of material when actuated or switched, and are typically used only for switching between two alternate discharge piping outlets.